Department of Entomology and Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI 53706, USA.
Proc Natl Acad Sci U S A. 2011 Jul 12;108(28):11500-5. doi: 10.1073/pnas.1100751108. Epub 2011 Jul 11.
Agronomic intensification has transformed many agricultural landscapes into expansive monocultures with little natural habitat. A pervasive concern is that such landscape simplification results in an increase in insect pest pressure, and thus an increased need for insecticides. We tested this hypothesis across a range of cropping systems in the Midwestern United States, using remotely sensed land cover data, data from a national census of farm management practices, and data from a regional crop pest monitoring network. We found that, independent of several other factors, the proportion of harvested cropland treated with insecticides increased with the proportion and patch size of cropland and decreased with the proportion of seminatural habitat in a county. We also found a positive relationship between the proportion of harvested cropland treated with insecticides and crop pest abundance, and a positive relationship between crop pest abundance and the proportion cropland in a county. These results provide broad correlative support for the hypothesized link between landscape simplification, pest pressure, and insecticide use. Using regression coefficients from our analysis, we estimate that, across the seven-state region in 2007, landscape simplification was associated with insecticide application to 1.4 million hectares and an increase in direct costs totaling between $34 and $103 million. Both the direct and indirect environmental costs of landscape simplification should be considered in design of land use policy that balances multiple ecosystem goods and services.
农艺强化已经将许多农业景观转变为广阔的单一栽培，几乎没有自然栖息地。一个普遍关注的问题是，这种景观简化导致虫害压力增加，从而增加了对杀虫剂的需求。我们在美国中西部的一系列种植系统中测试了这一假设，使用遥感土地覆盖数据、全国农场管理实践普查数据以及区域性作物害虫监测网络的数据。我们发现，独立于其他几个因素，用杀虫剂处理的收获耕地的比例随着耕地的比例和斑块大小的增加而增加，随着县内半自然栖息地的比例的增加而减少。我们还发现，用杀虫剂处理的收获耕地的比例与作物害虫的丰度之间存在正相关关系，而作物害虫的丰度与县内耕地的比例之间也存在正相关关系。这些结果为景观简化、害虫压力和杀虫剂使用之间假设的联系提供了广泛的相关支持。利用我们分析中的回归系数，我们估计在 2007 年的七个州的区域中，景观简化与 140 万公顷的杀虫剂施用以及总计 3400 万至 1.03 亿美元的直接成本增加有关。在平衡多种生态系统商品和服务的土地利用政策设计中，应考虑景观简化的直接和间接环境成本。
